Suppose a bar 1 m long expands .5 cm when heated. By how much will a bar 100 m long of the same material expand when similarly heated?

If each one meter expands a half centimeter, then one hundred meters will expand 100*.5cm. Think on that.


If there is a positive change in Thermal Energy is there a gain or loss in energy?


To understand how much a bar of 100 m will expand when heated, you can use the concept of linear expansion. Linear expansion is the increase in length of an object when it is heated.

Given that the bar expands 0.5 cm when heated, we need to find the expansion for a bar that is 100 m long.

To do this, we can use the proportion:

(original length of 1 m) / (expansion of 0.5 cm) = (length of 100 m) / (unknown expansion)

Rearranging the proportion and solving for the unknown expansion:

unknown expansion = (length of 100 m) * (expansion of 0.5 cm) / (original length of 1 m)

Plugging in the values:

unknown expansion = 100 m * 0.5 cm / 1 m


unknown expansion = 50 cm

Therefore, a bar of 100 m long will expand by 50 cm when similarly heated.

Now, regarding your question about thermal energy:

If there is a positive change in thermal energy, it means there is a gain in energy. When an object is heated, its molecules gain energy and become more active, leading to an increase in thermal energy. Conversely, when there is a negative change in thermal energy, it means there is a loss of energy, indicating that the object is cooling down.